76C-11 |
Effects of post-harvest treatments on the microbiological quality and pesticide residues of lowbush blueberries |
K. M. CROWE1, A. A. Bushway, and R. J. Bushway. (1) Department of Food Science and Human Nutrition, University of Maine, Holmes Hall, Orono, ME 04469
Lowbush blueberries of the species Vaccinum angustifolium are native to the Northeast United States. In the state of Maine, lowbush blueberries are commercially managed and harvested each year to be marketed as either IQF (individually quick frozen) or fresh pack. Since Maine wild blueberries are processed for IQF at the field level, good crop management and post-harvest treatments must be in place in order to ensure high quality products. The objective of this study was to examine the influence of post-harvest treatments on the microbiological quality and the residual phosmet levels of lowbush blueberries. Field samples were collected from one of Maine’s commercial blueberry fields immediately after treatment with aerial sprays of Imidan 70-W. Sampling continued each week through harvest. Berries were subjected to 500mL sprays of 100ppm chlorine, 0.5% hydrogen peroxide, 0.5% citric acid, distilled water, and a commercial FIT® wash. Microbiological analysis of total aerobes, yeast, and mold were conducted using FDA Standard Methods. Residual phosmet was measured by GC/MS. Reductions of 1 log or less were seen in the microbial load of washed blueberries; however, statistically significant differences were not detected among the treatments (p<0.05). Over the five weeks pre-harvest, our results showed that as residual phosmet levels decreased, the microbial load increased. Hydrogen peroxide, chlorine, and FIT® were among the most effective at removing residual phosmet from the berries. From the initial spray with Imidan 70-W until harvest, phosmet levels decreased 80% on average. The Maine Wild Blueberry industry currently includes a chlorinated water wash during processing of IQF berries. These results suggest that a chlorine wash is effective in reducing residual phosmet and in reducing microbial loads, but it is not a reliable means for ensuring microbial safety of IQF processed blueberries.
Session 76C, Fruit & Vegetable Product: Fresh Fruits and Vegetables
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